Which of the following is an example of a primary source? A: Diaries and letters from the 1880s published in a recent book of collected diaries and letters from the 1880s B: an encyclopedia article citing events from the 1880s and giving a list of works cited C: a recently publishedd history book that cites diaries and letters from the 1880s D: a newspaper article published in the 1980s that reports on an event in the 1880s